Im after a new digital camera, a 4MP one as I'm going to be taking landscape shots.

I need one that is light, has many options and can be controlled, eg shutter speed control, ISO control, aperture control, exposure control.

Im also after at least a 4X optical zoom lens. If the cam could save images in TIFF format that would be a great plus point!

I have around £350 to spend.

I have been looking at the Pentax optio 450, which seems to be a good camera, has 4 sec - 1/4000 sec (and then it says 1/1000 sec in manual, but does that mean it will only do 1/1000, or does it do from 1/1000 to 4 sec?). Any one have any opinions on this cam?

Format-RAW should be considered as your format instead of TIFF. the reasoning is the rather large latitude of control you have in post shooting over any other formats including TIFF. TIFF is a rather large file too. a basic RAW converter is included with a camera that allows acces to the RAW file.

MP- you should consider your final output printed size before you decide on the imager MP. in the long run its what you consider adequate in printed image quality that will matter. also consider the imager physical size too. smaller dimensions and more MP can generally cause higher "noise" in the image.

Weight/controls/size- all digicams are relatively light so as an issue a few grams here and ther aren't going to really matter. the smaller the camera the less easy access to the contols there are due to size constraints. realize that the ergonomics of the camera are very important.

Lens- 95% of digicams stop at the 35 or 38mm equivelent of wide angle. for close in landscapes (someones beautiful garden in say their city backyard) you can find that an issue. screwing in a aux lens can be problematic in itself. if it is not one specifically designed for your lens you can have issuse of image softness, barrel distortion, or CA chromatic abberation (color fringing). even those designed for your original lens will reduce overall quality. having a 28mm equivelent built in at your wide angle end can save a lot of potentials problems. you have to try to be prepared for as many situations as possible.

suggested cameras: Minolta A1, Nikon 5400, Olympus 5060

all of the above mentioned cameras have most of the mentioned items discused also have memory card types in common too. to shoot RAW or TIFF you need room. CF cards have the lowest cost per MB on the market today. a high quality 512MB CF card will cost you ~$170US today a HQ SD card same size will cost you ~$225US and up. there are adapters that allow the use of both xD and SD in a CF slotted camera but it is physically impossible to do the reverse. the olympus actually takes 3 different types w/o adapters SM xD and CF. you will find any camera that is shooting larger images will have a CF slot. even Sony has broken down and put a CF slot on their new 828

all 3 of those cameras go well beyond you current wants/needs as of what you think of doing at the moment.